128 THK entomologist's RPX'ORI). 



scheme of lepidopterous larv«, i called attention to long ago m a papBi- 

 on " The genus Smerinthus " [Ent. Record, vol. vi., p. 175) ; and I 

 have always considered that the coloration of black day-flying species 

 such as (hio)ihria nibricollis and Tanaura atrata, was probably due to 

 their obtaining protection owing to the strong contrasts between lights 

 and shadows in our woods at the period when they are on the wing, 

 although my opportunities of observing these species have been so few 

 that I mention this with considerable diffidence. If my suggestion in 

 regard to the butterfly's preference for sunlight is borne out by the 

 facts of the case, it should afford a test as to whether the coloration of 

 any particular species is of a cryptic or warning character, as the 

 latter forms should show a certain disregard to passmg clouds (if 

 such things ever happen in the tropics), in contrast with the former. — 

 A. W. Bacot, F.E.S., 154, Lower Clapton Road. N.E. Jnniiani 21fh, 

 1904. 



" Types " in Natural History. — I am pleased to see that Dr. 

 Chapman, in his notice of " The Revision of the Sphingides," has dwelt 

 [Ent. Record, xv., pp. 310-11) on the meaning of the word " type," and 

 has attacked the utterly unscientific position of those who hold that 

 the type of a species is " the form which is i^tippoaed to be the 

 commonest, the most widely spread, or the most ancient, etc." The 

 italics are mine. Is it conceivable that any thoughtful entomologist 

 has really imagined a "type "form exists in nature, apart from the 

 subjectivity of the individual student ? If so, I should much like to be 

 enlightened as to what it is, and how a stable nomenclature can 

 possibly be based upon it. The words which I have just quoted are 

 pregnant with suggestion, and embody a good deal of the matter which 

 has been prominently in my mind for some weeks past, as the result 

 of a conversation which I had with another entomologist on the subject. 

 The only fault in Dr. Chapman's clear and valuable paragraph is at the 

 very end, where he speaks of the " confusion of two different 

 meanings, etc." The word " two " should have been left out, for 

 certainly many more than two distinct meanings are possible when 

 we begin to attach some pseudo-philosophical, or pseudo-biological 

 significance to the word. Several have occurred to me, and there 

 must be many others which I have not thought of, or which 1 have 

 not clearly differentiated in thought from those which I shall mention. 

 Firstly there is the iiiimeriral type, which is apparently what the author 

 quoted by Dr. Chapman means -or thinks he means — by " the true 

 type," /.''., the form of which the lai'gest number of examples exists on 

 the face of tlie globe. ])ut this is manifestly undiscoverable, and even 

 if we could become omniscient in this respect, we should, with many 

 species, have to re-model our conceptions every day, or every year, 

 according to the numerical fluctuations, to say nothing of the " personal 

 equation," for which there would be plenty of room in the assigning 

 of hosts of slightly aberrant forms, either to the type oi' to an aberra- 

 tion. Secondly, there is the }>]ujlo<ienetic type, or the form which is the 

 most ancient still surviving. But here, again, we are absolutely 

 without knowledge, and should have to rest on speculation — with what 

 results to nomenclature can hv better imagined than described. 

 Thirdly, there is the local type, or the form dominant in a particular 

 locality. This is probably what our friends really want us to aci<now- 

 ledge as the type, if we give the word "locality"' a rather wide 



